Aberrant histone modification in peripheral blood CD4+ T lymphocytes in oral lichen planus

To investigate the histone acetylation level and histone deacetylase (HDAC) activity of peripheral blood CD4+ T lymphocytes in patients with oral lichen planus (OLP).

Twenty-three OLP patients were selected from August 2016 to January 2017 from the Stomatological Hospital, Southern Medical University. The diagnosis was confirmed by pathology, and the lesions were divided into a nonerosive OLP group (11 cases) and an erosive OLP group (12 cases). Ten healthy sex- and age-matched volunteers served as controls. Immunomagnetic beads were used to separate CD4+ T lymphocytes, and histones and nucleoproteins were extracted. The global histone H3/H4 acetylation levels and HDAC activity of CD4+ T lymphocytes from all subjects were detected by ELISA. The differences between the OLP and control groups were statistically analyzed.

Global histone H3 hypoacetylation was observed in the OLP group compared with the control group (u = -2.410, P = 0.012). However, there was no significant difference in the serum CD4+ T lymphocyte histone H4 acetylation level between the OLP and control group (u = -1.412, P = 0.158). HDAC activity was significantly higher in the OLP group than in the healthy control group (F = 5.749, P = 0.023), and much higher HDAC activity was observed in the erosive group than in the nonerosive (P = 0.014) and healthy control groups (P = 0.001). The degree of histone H3 acetylation correlated negatively with increased HDAC activity in the OLP group (r_s = -0.771, P < 0.001). There was no correlation between the level of histone H3 acetylation and HDAC activity in the healthy control group (r_s = 0.382, P = 0.276). The histone H4 acetylation level in the OLP group showed no correlation with HDAC activity (r_s = 0.149, P = 0.498), and the histone H4 acetylation level in the control group also showed no correlation with HDAC activity (r_s = 0.527, P = 0.117).

Abnormal histone acetylation of CD4+ T lymphocytes in the peripheral blood of patients with OLP was identified and could be related to HDAC activity, suggesting that the epigenetic modification of histone acetylation may play a role in the pathogenesis of OLP.